to the van before I took it and point at any damage I found and took pictures of him doing so.

At our first gas stop, I knew to get out of the van and watch the guy zero out the pump before he started pumping my gas. I also knew to watch him closely, as some will swap out a 500 peso note for a 50 peso note when you aren't watching, and claim you only gave them 50. Sure enough, the guy was wearing bib overalls and very quickly put the 500 note in one side and pulled the 50 out of the other and then claimed I only gave him the 50. I reached over and pulled the 500 out of his overalls. Oh...he said something in Spanish and that was that.

There might be some good info here, this couple lived in MX for a couple of years (will start at the driving scams)
https://www.youtube.com/watch?v=0M_4BuaqWyQ